Answer:
Explanation:
The magnetic field of a plane-polarized electromagnetic wave moving in the z-direction is given by :
.....(1)
The general equation of the magnetic field wave is given by :
....(2)
Equation (1) is in form of equation (2), if we compare equation (1) and (2) we find that,
We need to find the frequency of the wave. It is given by :
So, the frequency of the wave is
Answer:
c. Kinetic energy
Explanation:
The two types of energy involved in this problem are:
- Potential energy: it is the energy possessed by an object due to its position. It is calculated as
where
m is the mass of the object
g is the acceleration due to gravity
h is the height of the object relative to the ground
From the formula, we see that the higher the object is above the ground (higher h), the larger the potential energy of the object. In this problem, the pig is falling down, so the value of h is decreasing, therefore the potential energy is decreasing as well.
- Kinetic energy: it is the energy possessed by an object due to its motion. It is given by:
where
m is the mass of the object
v is its speed
In this problem, as the pig falls down, it accelerates, so its speed increases: since the kinetic energy is proportional to the square of the speed, as the speed increases, its kinetic energy increases too. So, the correct answer is
c. Kinetic energy